The invention relates to a sealing device for a filling opening, especially for sealing against the escape of fuel fumes when filling stationary or mobile supply tanks, with the features wherein a seal is located in the vicinity of a filling opening and, in its sealing position, abuts an object such as a filling device inserted into a filling opening. The invention also relates a method for control of the sealing device.
It is known that the escape of fuel fumes from the filling opening of the tank (supply tube or filler neck) when filling motor vehicles with fuel can be prevented by mechanically acting sealing arrangements. There are various embodiments.
The seal can be attached to the filling device (often referred to as the gas hose nozzle), whereupon problems arise with adaptation to the model-specific environment of the mouth of the filler neck. Arrangements of this kind are known especially in conjunction with an active emission recovery system at the filling station.
The seal can be located in the filler neck itself, however (according to EP 0 484 642 A1 for example). As the level rises and the internal pressure in the tank increases, any fumes that escape are not guided in a countercurrent through the intake to the outside but through a filter, especially an activated charcoal filter, which traps the fuel components. Occasionally however there are sharp edges on the filling nozzle or the latter is inserted carelessly, so that a static seal on the neck side is liable to be destroyed.
It has also been proposed to solve the problem by employing measures involving flow technology (so-called liquid seal technology), in which a suction flow is generated during filling as the fuel flows into a filler neck with a correspondingly shaped cross section. The pressure drops thus produced are intended to prevent fumes from escaping without using actual seals. It has been found however that such arrangements are cumbersome and expensive because they must be carefully adapted to each individual filling system design, and proper filling of the tank is made more difficult or at least slowed down.